Apparatus for desuperheating steam



Nov. 14, 1933. Q GORDON 1,935,195

APPARATUS FOR DESUPERHEATING STEAM Filed Oct. 8, 1930 2 Sheets-Sheet 1 h 3 g n 3 INVENTOR Charles W'G ordon.

ATTORNEY Nov. 14, 1933. c. w. GORDON 1,935,195

APPARATUS FOR DESUPBRHEATING STEAM Filed Oct. 1930 2 Sheets-Sheet 2 .z I ETR Q INV Ne Charles BY /ZQA ATTORNEY Patented Nov. 14, 1933 UN-ITED'ISTATIES' v 1,935,195 APPARATUS FOR DESUPERHEATING s'rEAM Charles W. Gordon, Munster, Ind., assignor to The Superheater Company, New York, N. Y.

Application October 8, 1930. Serial No. 487,215

r -10 Claims.

' long as the number of thermal units per unit' weightof .steam .is maintained constant at the inlet of thesuperheater.

In accordance withmy invention, themake-up water supplied to the desuperheater is .heated substantially to the boiling ,pointat the pressure within the .desuperhea'ter shell before being mingled with the water therein. Two ways of accomplishing this are illustrated in the drawings, but I do not limit myself to any particular means or method for doing this. Further in accordance with my invention, the .water level in the desu'perheater is kept constant and the'circulation stimulated by introducing the make-up water at the top of the down pass of the 'thermosiphonic circulation.

. In order that my invention, together with furtheir objects and advantages thereof, may be clearly understoodI will now describe in detail 5 in connection with the accompanying drawings a desuperheater apparatus embodying my invention. In said drawings,

Fig. 1 is a diagrammatic elevational view of a desuperheatingapparatus in accordance with my invention, parts beingbroken away for purposes of illustration; I

V Fig. 2 is a half elevationaland hal'f' sectional view of a desuperheater element. appearing in Fig. ,1;

one of the feedwater delivery pipes appearing in Fig. 2 and illustrating the nozzles used therewith.

In the apparatus illustrated, superheatedsteam whose temperature is .to be reduced is conducted through the pipe 10 into a desuperheater 12 and the steam of reduced temperature is discharged from element 12 through the pipe 14. The element 12 comprises a shell 16 the interior of which is divided by a tube sheet 18 and a partition 20 into a chamber 22 for superheated steam, chamber 24 for the 'desuperheated steamfand a water and steam chamber 26. In the operation of the apparatus, steam enters the chamber 22 from the pipe 10 and passes from chamber 22 to chamber 24 through inverted U-tubes 28, 28 arranged in a bundle within the chamber 26 and having their I lower ends expanded into the tube sheet 18. The superheat in the steamadmittedto desuperheater 12 is transmitted through the walls of the tubes 28 into a body of water 30 in the chamber 26 Fig. 3 is a detail view on an enlarged scale of whose normal levelis maintained substantially constant at the height of theline32 which is preferably above the upper end of the tube bundle. By maintaining the tube bundle completely'submerged, the apparatus is always in condition to 6o. deal with a high rate of flow of steam when desired. For maintaining the water level constant I have illustrated a known type of apparatus comprising a hollow member 34 inclined to the horizontal and supported so that the horizontal 6f planeincluding the line 32 cuts it approximately half waybetween its'ends. At its upper end member 34 is connected by a pipe ,36 to the. steam space in the upper portion of the shell 16 and the lower end of member 34 is connected bya pipe 38 74).

.to the water space within shell 16. Theupper portion of the member 34 therefor contains steam and the lower portion waterso that its average temperature depends upon the water level.v If

the water level falls, the member'34is heatedand expands whereas when the water level rises, member 34'is cooled and therefore contracts. These changes in length of member 34"are transmitted through suitable connections to a valve member,

not shown, within the'val've casing '38 so as to control the flow of water through, the water, inlet pipe 40 to thereby maintain constantthe level of the body of water 30. The connections for this purpose are shown as'comprisingrods 41 and 42 which are connected to the lever, 43 having afulcrum at 44and connected to theyalve stem 45 for operating such stem and ,the valve within casing 38.' The water level maybe expected therefore to be constant enough so'tnat the temperature of steam flowing out 0f. nozzle .14 is sub.- stantially constant for. any given position i of the member 734'. When installingra given apparatus the capacity can be predetermined, .within the limits fixed by the surface of the U-tubes, by positioning the water level apparatus so as to 95. prevent the water level from rising above 'a 'g'iven height. For emergency purposes, I have provided also a float operated valve in pipe 40in serieswith the valve contained in valve casing 46 and operated by a float inv chamber 48through suitable connections indicated by reference character 49.

The-capacity of an apparatus such as that .described depends in considerable measure upon the rapidity of the circulation of the water in shell 16. To promote the rapid circulation of ,this water I have left a space 50 between -the'outer row of tubes28 and the inner face. of shell 16 whose radial dimension is at least one-quarter of theradius of the shell 16.. It will be apparent be upward in the center of the shell and downward through the space 50 because of the steam bubbles formed by the transfer of heat to the water from the tubes 28. In order to prevent the stream of incoming feedwater from pipe from interfering with the natural circulation within shell 16 I introduce the make-up or feedwater into the shell through nozzles 52, 52 at the upper end of the space 50.

I have found, moreover, that the absorption of heat by water within shell 16 at the time it is converted into steam is much more eflicient and rapid than the absorption of heat by the water while being raised to the boiling point. I, therefore, prefer to raise the incoming water to the temperature of the water in body 26 before discharging the make-up water into such body. In Figs. 1 and 2 I have illustrated two means of so preheating the feedwater. for this purpose illustrated in Fig. 2, the feedwaterintroduced into shell 16 through pipe 40 is led first into a horizontal ring surrounding the tubes 28 and lying in the lower portion of the space 50. From the upper surface of "ring 54, tubes 56, 56 run up to the upper end of space and the nozzles 52 for discharging the feedwater into the body 26 are connected into the upper ends of the pipes 56. Further, this arrangement accelerates the thermo-siphonic circulation in shell 12 in that water in space 50 is cooler and denser than would otherwise be the case on ac count of the heat units absorbed from the water in such space by the water within tubes 56. In

case the space 50 is provided in tubes (not shown) supplied to the desuperheater.

external toshell 16, the tubes 56 will of course be brought into such external tubes.

Steam formed in the shell 16 may be utilized in any Way that is desired, the use to which such steam may be put depending in great measure upon the pressure maintained Within shell 16. It has been found convenient to discharge some of the steam generated within the desuperheater such as 12 into the main 10 for the superheated steam and in Fig. 1, I have shown an unrestricted connection 58 running from the outlet nozzle 60 at the top of shell 16 to a. connection with the steam pipe 10. The pressure in the shell 16 is therebymaintained the same as that of the steam Whatever the pressure within the superheater, the steam generated therein, being at the same temperature as the water, is an ideal medium for preheating the make-up water for such desuperheater to raise the temperature of the make-up water to that of the water within the desuperheater 12. For this purpose I have shown in Fig. 1 a steam connection 62 leading off from the connection 58 and arranged to conduct steam to a feedwater heater 64 of any known or desired type. Feedwater for desuperheater 12 may be forced into the heater 64 by a pump 66 in the pipe '70 and conducted from the feedwater heater to the desuperheater through pipe 40. A check valve 73 should be employed in line 40 to prevent water from desuperheater 12 from backing up into line 40. Condensate formed in the feedwater heater 64 may, if the feedwater heater is above the water level in the desuperheater 12,'be conducted back to the desuperheater 12 by gravity through pipes 74 and 76. If, however, conditions do not permit of gravity flow from the feedwater heater 64 to the desuperheater 12, the condensate may be taken from pipe 74 through pipe '78 to the suction side of the pump 66. A three-way valve is shown at the junction of pipes 76 a d. 8

In the arrangement to permit running of the condensate through either pipe '76 or I8 as may be desired. To prevent flow of steam into pump 66 when pipe 78 is in use, a trap 82 is preferably provided. Trap 82 is shown in pipe 74, but it may be in either pipe 74 or '78.

In case it is desired to furnish steam through pipe 14 of a higher temperature than that of the saturated steam generated in the boiler connected to pipe 10, a valved by-pass 84 may run directly between pipes 10 and 14. The valve in by-pass 84 may be thermostatically controlled if desired. A thermometer 86 is preferably inserted in the pipe 14 to determine the temperature of the steam delivered thereto.

'It has formerly been considered necessary to make the tube sheet such as 18 or the outer head 23 separate from the remainder of the casing of the steam inlet and outlet chambers. I have found, however, that the tube sheet such as 18 and head 23 may both be cast integral with the remainder of the steam end of the apparatus without giving rise to harmful stress during operation ofthe apparatus and such construction is illustrated in Fig. 2 This arrangement involves having partition 21 integral with sheet 18 and head 23, but eliminates one gasket joint and is further advantageous from a manufacturing and assembly standpoint.

What I claim is: f V

1. The combination in a desuperheater of a chamber adapted to contain water, a tube bundle in said chamber and forming the sole means of heating water therein, means to pass steam to be desuperheated through the tubes of said bundle, means to take off steam from said chamber, means to feed water to said chamber, and means to preheat said feedwater to a material extent and substantially solely by steam from said chamber. V 2. The combination in a desuperheater of a chamber containing water, a tube bundle in said chamber and forming the'sole means of heating water therein, means to pass steam to be desuperheated through the tubes of said bundle, means to take off steam from said chamber, means to feed water to said chamber, means to preheat said feedwater to a material extent and substantially solelyby steam from said chamber, and means to return condensate from said preheating means to said chamber.

.3. The combination in. a desuperheater of a chamber containing water, a tube bundle arranged in said chamber to cause when heated a thermal circulation of water, means to pass steam to be desuperheated through the tubes of said bundle, and means to introduce feedwater into the downward flow of the thermal circulation in said chamber at a point in the downward flow near the beginning thereof.

4. The combination as set forth in claim 3 together with means for preheating the feedwater before introducing it into the downward current of the chamber. v

'5. The combination in a desuperheater, of a shellhaving an internal chamberand-a tube bundle in said chamber arranged to provide a space for downward circulation of water between itself and the shell, means for passing steam to be desuperheated through said bundle, and means to introduce feedwater into said space at a level near the top of the bundle.

6. The combination as set forth in claim 5 and in which the means for introducing feedwater comprise-tubes extending upwardly between the tube bundle and the shell.

7. The combination as set forth in claim 5 and in which the means for introducing feedwater includes a ring surrounding the lower portion of the tube bundle, and tubes running upward from said ring between the tube bundle and the shell and having outlet nozzles at levels near the top of the bundle.

8. A desuperheater having a space for the downfiow of water to be evaporatedin the desuperheating operation, and means for conducting make-up water through said space in indirect heat absorbing relation to the water to be evaporated.

9. The combination of a chamber adapted to contain water, a tube bundle in said chamber arranged to contact with water therein, means to pass steam to be desuperheated through the tubes chamber, said chamber and said bundle arranged to cause when heated a thermal circulation of water longitudinally of the chamber, means to pass steam to be desuperheated through the tubes of said bundle, and means to introduce feedwater into the downward flow of the thermal circulation in said chamber at a point in such downward flow near the upper end thereof.

' CHARLES W. GORDON. 

